Manually-activated postage meters are well-known in the art. Typically, an envelope or a tape is manually fed under a print head for printing an indicium thereon. The print head is fixedly mounted in the postage meter, and a sensing device is used to sense the presence of the envelope under the print head. In order to print the indicium with minimum distortion, the speed of the envelope must be controlled to match the print speed of the print head. Thus, some mechanism must be used to synchronize the movement of the envelope to the print head. U.S. Pat. No. 4,168,533 (Schwartz) discloses a micro-computerized miniature postage meter, wherein a microcomputer is used to actuate an inkjet printing device to project ink droplets onto a substrate moving relative to the printing device. In particular, the movement of the printing device relative to the substrate is detected by an encoded rotating wheel mounted on the lower contact surface of the printing device. The rotating wheel is coupled to an interrupter disc, which is adapted to provide signal pulses for coordinating the proper time for actuating of the printing device. With such a design, the postage meter becomes costly to produce and to sell.
Thus, it is advantageous and desirable to provide a simple synchronization method and apparatus for use in a value metering system, such as a postage meter.